'More suited'? At 4?
At 4, you do stuff because you enjoy it. Being good or bad is completely and utterly irrelevant. Is she having fun?
I have three kids in dance. The eldest is now 15 and has been in ballet since she was three. She is not a natural dancer, has absolutely no chance at all of dancing professionally (even if she wanted to, which she doesn't) but loves it. It is fantastic for her confidence, her determination, and her personal discipline (this follows through into her determination to keep up with homework, get the best grades she can, etc)
Middle kid is 13. He started dance at 2 because he literally can't stand still if music is playing, and dd1's dance teacher just said 'for goodness sake, let him join in'. He has entirely his own sense of rhythm, but he loves it.
My youngest is 12. She has cerebral palsy. She has been taking ballet since she was 5 (when she first started, she couldn't stand unaided). She adores it, is in a regular dance class, and the stretching and movement have been an absolute godsend for her, and have reduced the amount of necessary physiotherapy. At 12 with cp, she is in no way at all capable of keeping up with her peers. Pipe dream. No one gives a toss. I am utterly boggles that in your world view I should have redirected her years ago into something more 'suitable'.
I am actually staggered that at 4 you are eyeing up your kid and judging her worth to continue an activity based on her 4 year old body shape and outdated notions of grace. I have yet to see any grace develop across a ballet class until about 10.
And I've seen a few.
If you had told me at four that dd1 would dance pointe, I would have laughed. But she does. She loves it. She is under no illusions as to her ability. When she says 'my feet are terrible!' And grins, she doesn't mean that they are 'ugly dancer feet', she means that despite her best efforts, she doesn't have the 'right' flex and movement to be a professional. And she cares not a jot. And she dances about ten hours a week.
Should you 'let' her do something she enjoys? Is that even a real question? I mean, I get the angst about mocking, really I do. (I have a kid with cp in ballet, for goodness sake) but maybe you should be more concerned about enjoyment and fun for your dd, rather than what anyone else might think at some notional point in the future?